If the issue was not present before, and if everything is the same as it was apart from your internet connection, it may be that your internet provider is checking for IRC connections on your new line and is disconnecting them.

You could contact them to ask if they are doing this - note that level 1 support may not be aware of such a policy, so you may need to press the issue. If it turns out that this is the case, please let us know.

Alternatively, if you try connecting through a VPN, do you see the same issue?